From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Mon, 27 Jul 2015 15:54:09 +0000 (+0300)
Subject: Don't assume that PageIsEmpty() returns true on an all-zeros page.
X-Git-Tag: REL9_2_14~87
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0abe9554fc793f05d5c7f18b4b6682d9f1154922;p=thirdparty%2Fpostgresql.git

Don't assume that PageIsEmpty() returns true on an all-zeros page.

It does currently, and I don't see us changing that any time soon, but we
don't make that assumption anywhere else.

Per Tom Lane's suggestion. Backpatch to 9.2, like the previous patch that
added this assumption.
---

diff --git a/src/backend/access/spgist/spgvacuum.c b/src/backend/access/spgist/spgvacuum.c
index 5b457f67945..7092647c039 100644
--- a/src/backend/access/spgist/spgvacuum.c
+++ b/src/backend/access/spgist/spgvacuum.c
@@ -656,7 +656,7 @@ spgvacuumpage(spgBulkDeleteState *bds, BlockNumber blkno)
 	 */
 	if (!SpGistBlockIsRoot(blkno))
 	{
-		if (PageIsEmpty(page))
+		if (PageIsNew(page) || PageIsEmpty(page))
 		{
 			RecordFreeIndexPage(index, blkno);
 			bds->stats->pages_deleted++;